This invention relates to method and apparatus for in situ cleaning of suction ducts which are utilized in an air exhaust system for removing particles of machining entrained in the air at a machining station. More particularly, this invention relates to method and apparatus for cleaning such suction ducts via a newly improved system for initially feeding the system through the duct. During the machining of a part, machines, such as milling or grinding machines, cast off fine waste particles. At least some of such particles remain entrained in the air adjacent the machines, and contaminate the breathing air. Such machines typically utilize cooling oil to maintain the cutting tool at a predetermined temperature and a portion of the oil will form into mist which will also be entrained in the air in and about the grinding and milling machines. In machine shops, environmental control, air and dirt exhaust systems have been provided for exhausting air adjacent milling machines and grinding machines so that the waste particles of machining and the oil mist which is entrained in the air, are drawn away from the machine and the machine operator. As the dirt and oil laden air are drawn through the exhaust ducts, some of the dirt and oil will gravitate to and adhere to the inside wall of the exhaust ducts. Continued buildup of the oil and dirt in the ducts will tend to close the ducts and the vacuum forces upstream of the oil and dirt accumulation will be reduced to a level insufficient to maintain an efficient exhaust system. It has been conventional to periodically dismantle the ducts into duct sections, deposit the duct sections in a liquid filled vat and then "boil" the insides of the ducts or conduit sections. This method is of course time consuming, expensive and renders the entire machining operation inoperative during the cleaning process. Accordingly, it is an object of the present invention to provide a new and novel method and apparatus for the in situ cleaning of an air and dirt evacuation exhaust system.
The duct work conventionally utilized in an air evacuation system extends overhead for a substantial distance throughout a machining plant. It has been found that the dirt, sludge, and scale which accumulate on the inside of the pipes can be removed from the duct wall via a fluid emitting nozzle, which emits fluid against the accumulated sludge. Due to the extreme length of the exhaust ducts, the initial feeding of a fluid emitting nozzle or the like through the duct has posed a substantial problem. Accordingly, it is another object of the present invention to provide method and apparatus for cleaning suction ducts which includes new and novel apparatus for initially feeding the fluid emitting member through the duct.
The duct conventionally used in suction systems of the type described have a series of end-to-end, coupled duct sections which successively increase in diameter from the inlet end to the outlet end. The suction system of the type described sets up substantial air drawing forces which will be sufficient to draw items disposed in the duct through the duct. The apparatus constructed according to the present invention contemplates a "parachute" or "umbrella" type draft member which is disposed in the pipe or exhaust duct to be drawn by the vacuum forces in a downstream path of travel. The member being sucked downstream is attached to a draft line so that the draft line is drawn therewith to the outlet end whereby the downstream end of the line can be attached to a wench or the like at the downstream end of the duct. The upstream end of the line is coupled to a fluid emitting nozzle, adjacent the inlet duct end, so that the line, as it is moved downstream by the wench draws the nozzle through the duct. Accordingly, it is a further object of the present invention to provide method and apparatus for cleaning suction ducts of the type described which incorporates a draft member that is initially drawn downstream by the suction forces created by the dirt and air evacuating system.
It is another object of the present invention to provide a method and apparatus of the type described including mechanism for initially drawing a draft line member through a suction duct from the inlet end thereof to an outlet end thereof.
The duct sections successively decrease in diameter in a direction from the outlet duct end to the outlet duct end so that the suction forces at the upstream end are sufficient to draw waste particles of machining away from the machines located at the upstream end. Accordingly, it is yet another object of the present invention to provide method and apparatus of the type described including a draft member which, as it is drawn downstream, which will be expansible and contractible so as to remain in intimate engagement with the inside of the varying diameter duct sections.
It is yet another object of the present invention to provide method and apparatus for cleaning suction ducts and incorporating a parachute type draft member for drawing the draft line through the duct.
Yet another object of the present invention is to provide method and apparatus of the type described including a draft line having a downstream draft section which is relatively lightweight for movement with a parachute type draft member and an upstream, relatively heavier, draft line member for coupling the lightweight line to a fluid emitting nozzle.
Other objects and advantages of the present invention will become apparent to those of ordinary skill in the art as the description thereof proceeds.